This invention relates generally to phosphorus containing compounds useful as additives in lubricants and more specifically to reaction products of inorganic phosphorus containing acids or anhydrides, including partial and total sulfur analogs thereof, a boron compound and ashless dispersants. The products are oil-soluble and impart antiwear and extreme pressure (EP) properties and antioxidancy to lubricating oils including functional fluids.
Nitrogen and phosphorus containing succinic acid derivatives are disclosed in U.S. Pat. No. 3,502,677 for use in lubricants, fuels and power transmitting fluids to provide antiwear properties in addition to dispersancy. We have now prepared antiwear compositions of inorganic phosphorus containing acids and ashless dispersants in oil-soluble form which provide improved oxidation performance as well as protection for rubber seals.